Monday, November 26, 2012

Deconstructing The Olympus OM H.Zuiko 24mm f/2.8

"Eureka!": Canon T2i, EF-S 60mm f/2.8 Macro USM
     Well.  I am not as prepared today as I thought I was.  I have a pile of things I want to blog about, but they all seem to get piled up on one another, and then i go to write and discover that I am missing some of the pictures I need.

     Never fear, though, for I have a topic, it just wasn't the one I was planning on, although it makes sense in the natural progression of things. So, without further ado, I dismantle the Olympus Zuiko 24/2.8.

     It really is pretty amazing how these things are put together inside. I never really understood the cost of a lens until I started taking them apart.  They are pretty much a modern marvel of mechanics.  I bow to anyone who designs optics. I can't imagine anything more challenging.

    Now, if you read my last post, I said I was going to show you what happens when you go into a lens from the front. If you recall, I have two copies of this lens.  I gave up on the first copy, and now I need to clean some gunk and fix the aperture in the second, and optically superior copy.  This is the one I want to keep.

   So I gathered my tools.  You will laugh when you see them. Please do. I deserve to be laughed at (and probably chastised) for using them.  Better tools are on my Christmas list this year.

   The first task is to get the front retaining ring off.  This is the piece with the writing on it.  There are two little slots on opposite sides of the retaining ring. These are for a spanner wrench, which is a special, and surprising expensive tool.  I have fashioned my own.

The elegant spanner

    A paper clip works, but you have to be careful.  Since it is obviously not the appropriate tool, if it slips, which it is prone to do, you can scratch something pretty good.

   Once you get it loose you can unscrew it more easily using a friction tool.  You can get a set from They're basically just a set of rubber cones("It's a cone!").  You can find the other proper tools there as well. Here is my friction tool(Hee hee, I said "friction tool"!).

Purple nitrile glove and water bottle cap... action.

     Once you get it off, you're in dangerous territory.  Don't turn the thing over, or things will come off, and you will 100% most definitely lose the tiny ball bearing that makes the aperture clicks for each stop.

     You will lift the retaining ring off and also the ring with the filter thread on it.  Underneath will be a silver ring with some holes in it that the ball bearing fits into. The best way to keep from losing the ball bearing is to remove the aperture ring(the ring with all the teeth) and the silver piece together(hold them together) and set them aside as a single, assembled group.  Lift up and off.

OMG, It's the ball bearing!

Then you will see a little stainless notch (it fits into a hole in the aperture ring).  This is the physical connection between the aperture and the aperture ring.

Aperture Lever
     Now, using your spanner(actually your fingers might work, mine did), you can unscrew a large portion of the optics as one piece.  If you need to clean in there, then you can further dismantle it.  Fortunately, I didn't need to get in there.  My problems were behind these elements. Here is what the piece looks like.

Front optical elements

     Once you get the front optical elements out, Voila! you have reached the aperture. A ridiculously complex little thing.  The two screws that attached the aperture lever to the aperture had fallen out(they fell out of the lens during an earlier operation, so i knew something was wrong somewhere), and to my luck and surprise, the dust spot that was showing up in the bokeh was on the element you see directly below.  I blew out the inside of the lens with the rocket blower and cleaned the element with some lens cleaner and a microfiber cloth.

Aperture open

Aperture stopped down to f/16

These screws came loose and were screwing everything up.

Now. All you have to do is put it back together.  It's important to pay attention to what you're doing so you remember how it goes back together.  As far as what I did here, it's not too hard.  You just screw the optical elements in until the unit is finger tight.  Then you put the aperture ring back on, making sure the aperture lever fits in the little hole in the ring(remember to do this with the other rings together as a group as to not lose the ball bearing). Once the aperture ring is lined up correctly, you can screw the retaining ring back on using your friction tool, and at the end, your spanner to tighten it up.

     I may have over simplified it a little bit, but generally every piece has some little notches that have to line up to allow everything to snap into place correctly. You can't put it back together wrong.  Now if you do some other things, you can put it back together wrong, so don't tear this lens apart with reckless abandon. But for this procedure you're safe.  When you start taking screws out, make sure you keep track of them(they are tiny) and remember what goes where.  Also, if you start taking individual elements out, make sure you don't put them back in facing the wrong direction.  You're done for if you do. Please bear in mind that most of these pictures are much larger than actual size.

   Of course, good intentions be damned. I have a perfectly working aperture now, but it appears a new planet transits the sun.
Could that be Mercury in its transit of the sun?

(P.S. If you like athletic Greek women you should do a google image search for "voula" like I did when I was trying to make sure I spelled voila correctly)

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